The present invention relates to an energy efficient condensing gas boiler, and more particularly, the present invention relates to a novel condensate trap for use with such a boiler.
Condensing boilers are known and are disclosed, for instance, by U.S. Pat. No. 6,401,669 B1 issued to Macgowan et al., U.S. Pat. No. 6,662,758 B1 issued to Shin, U.S. Pat. No. 6,907,846 issued to Hur et al., and U.S. Pat. No. 4,480,591 issued to Deckers. Such boilers are used in residential and commercial buildings for heating water and for supplying the hot water for space heating or domestic hot water purposes.
A condensing gas boiler uses combustion heat generated by burning gas with a burner to directly heat circulating water and re-absorbs condensed latent heat in exhaust gas to improve thermal efficiency. The boiler converts the latent heat of condensation into useful energy instead of expelling it with exhaust gases. Accordingly, flue gas is discharged from a condensing boiler only after its temperature has been lowered by heat exchange to below its dew point.
Water droplets form on the walls of heat exchangers of condensing boilers in areas where the flue gas temperature cools to below, for instance, about 140° F. As an example of the amount of condensation produced within a condensing boiler, a typical condensing boiler generating about 100,000 btu of heat for one hour will produce about one to two gallons of liquid condensate.
Accordingly, the condensed water is required to be collected and discharged from the boiler. The condensation is slightly acidic, typically having a pH of about 3.5 to 4.5. Some jurisdictions require the condensation to be neutralized before disposal. Condensing gas boilers typically include condensate traps that use some of the condensate to block and prevent the escape of flue gas through the condensate discharge port of the boiler.
Although the above referenced condensing gas boilers may be satisfactory for their intended purpose, there is a need for an energy efficient condensing gas boiler having improvements with respect to condensate discharge.